1. Technical Field
This invention relates to a document management system and in particular to document tampering prevention when the image data of a document created with paper is managed.
2. Related Art
Nowadays, various documents widely are created as electronic data and are managed and processed. In this case, the document may be created as an electronic document; often a document created with paper may be read using a scanner to acquire image data for management and processing. To manage the document created with paper as image data, it is important to manage the relationship between the paper document and the data and prevent document tampering to prevent unauthorized use of the document.
In recent years, attention has been focused on an art of using special paper with fine dots printed thereon (containing various sheet-like media) and inputting characters, an image, etc., handwritten on the paper by the user as electronic information. The input data is transferred to a personal computer, a mobile telephone, etc., and can be stored in a magnetic disk unit or any other storage or can be transmitted as electronic mail. In this art, small dots are printed on the special paper with a spacing of about 0.3 mm, for example, and the dots contained in a grid of a predetermined size draw a different pattern for each grid. The dot pattern can represent position information of an address, etc. Then, the dot pattern is read with a dedicated pen incorporating optical read section such as a digital camera, for example, whereby it is made possible to determine the position of the pen point and a move trace on the special paper. As information of the position of the pen point and the move trace is processed, it is made possible to use the handwritten characters and image on the paper as electronic information.